Abstract: A serial printer comprises a carriage (21) which is movable parallel to a platen roller (11) and on which are mounted a character carrying disc (28) having a flexible blades, a stepping motor (26) for selecting the character to be printed, and a striker hammer (30, 31). The carriage is slidable on a cylindrical guide (17) and is provided with a pair of slider members (62, 63) which co-operate with a fixed bar (18) that is parallel to the guide (17) and to the platen roller (11). Mounted on the fixed bar (18) at the left-hand side of the printer is a key (70) which can co-operate with the slider members (62, 63) of the carriage to disconnect them from the bar (18) and to permit the carriage (21) to be swung down so that the character carrying disc (28) can be easily removed and replaced.

Abstract: Positioning device for a printer comprising a type carrier daisy wheel fitted on a carriage movable in front of the platen. The selection of type and movement of carriage are carried out by selection and transport motors of direct current type which are controlled by velocity servo motors through corresponding digital transducer and position counters. After a coarse positioning by the servo motor, the exact final position is reached and kept by exciting a couple of magnetic positioners whose rotor is keyed on the axes of the selection and transport motors.Economic solutions are also described to synchronize, during initialization of the machine, the content of the position counters with the effective positions of the daisy wheel and carriage.

Abstract: A serial printer comprises a carriage 32 movable parallel to a platen 14 and on which there is mounted a printing device 31, for example of the daisy wheel type. The guides 23, 25 on which the carriage slide are mounted on a frame 20 which can turn with respect to the fixed sides of the machine on pivots 16, 17 to allow easy replacement of the daisy wheel. A motor 70 located beneath the roller constituting the platen effects displacement of the carriage along the writing line by means of a steel cable 72 and a series of return pulleys 44, 45, 75, 82. The cable passes through coaxial holes 74, 84 in the pivots of the frame, in such a way that its conditions are not altered when the frame is turned. A unidirectional clutch 86 and a spring 89 coupled to one end 88 of the cable maintain the tension in the cable always constant, while providing a non-yielding anchorage when the motor pulls on that end of the cable.

Abstract: An angular position transducer for a rotating member comprising a notched disc connected to said member, an opto-electronic pair for sensing the angular position of said disc and a supporting shell for said pair which is fixable on the support of the rotating member coaxially to said member. The disc is fixable directly to the rotating member at a predetermined position with respect to the shell, and comprises a thin flexible lamina guided on its periphery by a guiding element adjacent to the notches. The flexibility of the lamina compensates for any disalignment and axial displacement of the rotating member. The position signal is periodic and is sent to the terminals of a reference resistor. A control circuit modifies the value of the resistor in order to stabilize the peak value of the position signal within predetermined narrow tolerance limits.

Abstract: An angular position transducer for a rotating member comprising a notched disc connected to said member, an opto-electronic pair for sensing the angular position of said disc and a supporting shell for said pair which is fixable on the support of the rotating member coaxially to said member. The disc is fixable directly to the rotating member at a predetermined position with respect to the shell, and comprises a thin flexible lamina guided on its periphery by a guiding element adjacent to the notches. The flexibility of the lamina compensates for any disalignment and axial displacement of the rotating member. The position signal is periodic and is sent to the terminals of a reference resistor. A control circuit modifies the value of the resistor in order to stabilize the peak value of the position signal within predetermined narrow tolerance limits.

Abstract: A serial printing device comprises a type drum rotatably mounted on a carriage which can move parallely to a platen. On the periphery of the type drum are mounted a plurality of character-bearing elements urged against the drum by biasing means. A stepping motor rotates the drum for positioning a selected character-bearing element in front of the platen. A hammer is actuatable for pushing the selected character-bearing element radially outwardly relative to the drum against the action of the biasing means, and the drum is moved towards the platen simultaneously to the actuation of the hammer.